Or just know how to enable lockdown mode. On iOS that’s 5 rapid clicks of the power button, screen on or off, and it vibrates to let you know you got it without looking. Dunno what it might be for android, or if it varies by model.
It ends up like a newly rebooted phone; requires a typed passcode. It also provides quick links to medical ID info and the sos emergency call thing. It may, if you have an ID set up, also have a link to that, but I don’t have that configured so not super sure.